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Minerva Ortopedica e Traumatologica 2008 June;59(3):199-208

Copyright © 2008 EDIZIONI MINERVA MEDICA

language: Italian

The aneurysmal bone cyst: update on the diagnosis, treatment and prognosis

Fino A., Tosco P. M., Marone S., Brach Del Prever E. M., Gruppo Sarcomi Piemonte

Dipartimento di Ortopedia e Traumatologia AO CTO/Maria Adelaide, Torino, Italia

The aneurysmal bone cyst (ABC) is a rare benign bone lesion characterized by blood gaps separated by septa of mesenchymal tissue rich in spinale-cells, thin capillary and multinucleated giant cells and scattered with occasional trabecolar bone. It develops preferentially within 20 years of age and can present with pain and swelling. According to the pathogenetics assumptions the ABC may have a vascular, post-traumatic or genetic origin, as a rearranging of the short arm of chromosome 17 (17p11-13) has been detected in a third of the cases. Radiographically it appears as an osteolytic eccentric well-defined radiolucency in the long bone metaepiphysis region; common locations are vertebrae and pelvis. The cortical erosion is subperiosteal with lifting and poor reaction of periosteum, with a bone swelling. Computed tomography and magnetic resonance imaging show the limits and sometimes the levels of the liquids.
Arteriography shows sometimes vascular peduncles and allows a possible embolization in locations otherwise difficult to approach if not with major risks. The differential diagnosis should be made not only in case of youth bone cysts, but also in case of fibrous dysplasia, condromixoid fibroma, condroblastoma, giant cells tumor and osteoblastoma, injuries from which it develops in 30% of cases. The biopsy is essential to make the diagnosis. Treatment depends on the patient’s age, location, on the vascularization of injury, the size of the lesion and its extension. The inactive injury can be monitorized over time and heal spontaneously. The active or aggressive lesions have a risk of relapse and are treated with curettage or adjuvants, with or without bone graft; en bloc resection is indicated in eccentric lesions or expendable bones; embolization can be used in locations and vertebral lesions abundantly vascolarized, in combination with curettage. The use of demineralized bone matrix seems promising. The site of the ABC determines the type of treatment, which is not always easy if the lesion is located in long bones, if it includes growth cartilage, if it is localized in some parts of the pelvis or spine.